/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package org.apache.skywalking.oap.server.core.storage;

/**
 * @author peng-yongsheng
 *
 * 实现 StorageData 接口的有三类数据，分别对应三个抽象类：
 *      Metrics：
 *      Record
 *      RegisterSource
 * 在这三个抽象类下还有很多具体的实现类，这些实现类会根据对应的具体数据，扩展新的字段和方法。
 */
// SkyWalking 与 ORM 类似，会将索引中的一个 Document （或是数据库表中的一条数据）映射为一个 StorageData 对象。
public interface StorageData {
    // 返回该条数据的唯一标识
    String id();
}
